Marvel's Agents of S.H.I.E.L.D. season 6, episode 4, "Code Yellow," finally begins to answer some of the season's deepest mysteries. The story kicks off when Clark Gregg's Sarge (a.k.a. Not-Coulson) begins his actual mission on Earth. It seems Sarge and his team are hunting strange creatures who have infiltrated the human race, parasitic beings who take possession of host bodies. Unfortunately, there doesn't appear to be a surefire way of killing the parasites, and one of them actually breaks free and goes on a rampage in S.H.I.E.L.D.'s HQ, the Lighthouse.
Meanwhile, in a surprising twist, Sarge and his team move on to their next target, a face who will be familiar to any long-term viewers. Deke Shaw was introduced in Agents of S.H.I.E.L.D. season 5, the grandson of Fitz and Simmons from a dystopian future timeline in which the Earth was destroyed. Although S.H.I.E.L.D. successfully averted that timeline, Deke didn't fade from existence; instead, he's been thriving on Earth. At least, until Sarge and his team come calling.
The episode ends with both S.H.I.E.L.D. and Sarge taking prisoners; while next week will probably jump back to space, that does mean episode 6 should offer a lot of answers and explain just what Sarge and his group are up to on Earth. But for now, let's look at the questions raised by "Code Yellow."
8. What Is Not-Coulson's Purpose On Earth?
"Code Yellow" drops some major clues, suggesting that Not-Coulson may not be a villain after all. It seems that Sarge and his team are traveling across worlds (and possibly dimensions), hunting mysterious alien parasites that can take possession of human bodies. Their first mission upon arriving on Earth, in "Window of Opportunity", was to steal the right gems to power their tracker system, which has given them a map of temporal anomalies on Earth. They're now running through these anomalies, aiming to neutralize them.
7. What is Sarge Hunting?
Sarge and his team are hunting inter-dimensional beings who use leylines to travel either between worlds or (more likely) dimensions. The creatures are bat-like in appearance, clearly highly intelligent, and they take possession of a human host by forcing themselves down a person's mouth. Once inside the body, they attach themselves to the cardiovascular system and flood the body with a potent neurotoxin. This essentially kills the host, turning the human into a zombie piloted by the alien. The neurotoxin serves as a potent accelerant, a potential self-defense mechanism. It's possible this is the MCU version of the Brood, a parasitic alien race in the comics. While visually the Brood are very different to the parasites in Agents of S.H.I.E.L.D., that's not particularly surprising; the comic book race are basically a rip-off from the Alien films.
6. What Happened To Agent Keller?
Unfortunately, it seems that these parasites are pretty difficult to kill. Although Sarge probably thought he'd killed one of the creatures, in reality it survived, impaled inside its host by Sarge's knife. When S.H.I.E.L.D. removed the knife during the autopsy, the parasite awoke and went on a rampage, successfully forcing itself down Agent Keller's throat. Yo-Yo was forced to kill her lover before the parasite could trigger the accelerant and destroy the entire Lighthouse. It's interesting to note that just one parasite could apparently have brought down the Lighthouse, a building that - in one timeline - was able to survive the Earth's destruction. Perhaps an end-of-the-world scenario glimpsed in another episode, and seemingly associated with Sarge, was actually triggered by the parasites.
5. What Has Deke Been Doing For The Last 12 Months?
"Code Yellow" revealed that Deke has been using his technical genius, as well as his future knowledge, to establish himself as a social media influencer through a tech startup. Deke has started out by using Framework technology to advance virtual reality and create sophisticated VR games; one of them is "Remorath Rumble," inspired by the Remorath raid on the Lighthouse back in Agents of S.H.I.E.L.D. season 5. He's also working with real-world tech, attempting to recreate gravity-belt technology and integrate photon shields into prosthetic hands.
4. Is the Framework Tech Safe?
S.H.I.E.L.D. has kept Deke under observation, but given Mack's reaction to Deke's tech company, it's clear not everything has been reported in. In reality, the Framework technology that Deke is working with is deeply concerning; Framework tech is based on secrets from the Darkhold, an ancient book of arcane secrets, which means it most certainly isn't benign. Deke may have simply been using it to indulge in childish fantasies - complete with an objectified version of Daisy - but S.H.I.E.L.D. may come to wish he'd left this alone.
3. Who Is Playing Deke's Girlfriend?
Deke is dating a social media expert named Sequoia, a whimsical and not-too-bright woman who doesn't really mind Deke's self-absorption. Although Deke seems to have told Sequoia the truth about his origins, she clearly didn't believe it and thought he was just talking rubbish. She swiftly learns otherwise when she walks into the middle of a firefight between Sarge's gang and S.H.I.E.L.D. agents, all of whom are fighting over her boyfriend. Marvel fans will recognize Sequoia as Agents of S.H.I.E.L.D. showrunner Maurissa Tancharoen, making her first cameo in the show.
2. What Is A Code Yellow?
A "Code Yellow" is a priority extraction of an asset who's being monitored by S.H.I.E.L.D.. In Deke's case, Mack had Agent Trevor Khan keeping the time traveler under observation; a Code Yellow was called in as soon as Sarge and his team raided Deke's company. Khan, of course, was out of the loop and had no idea a murderer was running around with Phil Coulson's face.
1. What is S.H.I.E.L.D.'s Relationship With Local Law Enforcement?
S.H.I.E.L.D. has long had an uncomfortable relationship with the world's authorities, ever since they were compromised by Hydra and brought down by Steve Rogers in Captain America: The Winter Soldier. S.H.I.E.L.D. frequently struggled to gain a sense of legitimacy, not least back in season 4, when the United States Government attempted to take control of the organisation. It seems that Mack has succeeded in getting the authorities to recognize S.H.I.E.L.D., given there are now channels for local police departments to escalate strange events straight through to them. Presumably Mack has some sort of reporting line to the world's governments, perhaps even a hotline straight to the United Nations.
This is quite a major change for Agents of S.H.I.E.L.D.'s status quo, and it's interesting to see it done in the background rather than as a major plot. A longer season 6 may have devoted some time to exploring the political circles Mack needs to operate in, but this 13-episode abbreviated season drops the politics. It's a smart move.